Basic Biology II
The recent technological breakthrough has paved the way to convert adult differentiated cells such as skin cells into undifferentiated cells called human induced pluripotent stem (hiPS) cells that have an ability (pluripotency) to become all types of adult cells in human body. Because of this enormous ability, hiPS cells are thought to be the potential source of the cell-transplantation therapy for the treatment of diseases such as Parkinson's disease and diabetes mellitus. Despite this promising function of hiPS cells, due to its short history, there are many biological questions and practical hurdles to overcome. One questions is how we can distinguish fully converted genuine iPS cells from incompletely converted cells. Other important issues include development of technologies to derive and grow hiPS cells at high efficiency under completely animal-free conditions for future medical purposes. We have recently identified a signaling pathway (like a hormone that mediates biological information) that controls cell-cell attachment of pluripotent stem cells. Moreover, by controlling this pathway, we have established a method to grow another type of pluripotent cells, human embryonic stem (hES) cells, in a fully animal-free condition. In this proposal, we will investigate whether measuring the activity of this pathway could be helpful to select genuine iPS cells. Furthermore, by using this technology, we will develop a new method to efficiently generate and expand a new hiPS cell lines that are completely free from animal-derived materials.
Statement of Benefit to California:
Our research will focus on developing novel technologies by which hES and iPS cells can be propagated under completely defined conditions. The establishment of such a new method would impact virtually all hES and iPS cell-based application programs as it involves a common basic process to expand undifferentiated pluripotent stem cells before turning into any type of adult cells for the therapeutic purposes. It is therefore predictable that the new methodology will be promptly translated as an intellectual property to be commercialized, and would substantially activate the biotechnology field in the State of California. More importantly, the new methodology will be provided to the Institutes in California at the highest priority where the method will accelerate the process to apply the pluripotent cell-based transplantation approach for the clinical settings that would further substantiate the enhancement of the medical environment for California citizens.
EXECUTIVE SUMMARY The goal of this proposal is to investigate the role of a specific signaling pathway (“SSP”) in human induced pluripotent stem cells (hiPSCs) and explore basic mechanisms of its involvement in the reprogramming process. Elucidation of SSP’s role during reprogramming may help improve the production and maintenance of hiPSCs as a cell source for regenerative medicine. In Aim 1, the proposal addresses the idea that the regulatory mechanisms for cellular interactions and cell survival of iPSCs are integrated through SSP signaling. Aim 2 focuses on the development of tissue culture conditions that are fully defined and permit high-efficiency reprogramming. Reviewers believed the proposal addressed an important concept in human pluripotency research and appreciated its mechanistic emphasis. However, the proposal failed to address how SSP might play a unique role, and why this pathway, in particular, should be investigated. Reviewers expressed uncertainty regarding how results from the proposed experiments would lead to a better understanding of iPS technology. One reviewer appreciated the novel observation that adhesion to matrix and cell-cell attachment behaviors change when cells are reprogrammed to a pluripotent state. However, another reviewer viewed the project as lacking innovation because the proposal focused on ideas already studied in human embryonic stem cells. Although the reviewers acknowledged the proposal has potential for high impact, the project suffers from significant weaknesses in preliminary data and lacks an experimental focus on a key goal: increasing the efficiency of reprogrammed cell production. The experimental plan appeared overly focused on identifying signaling components in the relevant pathway instead of considering how manipulating SSP signaling could enhance production of iPS cells that are competent to differentiate into mature, functional cell types. Reviewers expressed a number of concerns about the preliminary data. For example, images purported to illustrate differences in cell-cell interactions and in the subcellular localization of signaling components between fully and partially reprogrammed cells were unconvincing. Also, controls and statistical information were absent from some of the figures. Additionally, there was an inadequate discussion of alternate plans and potential pitfalls, and descriptions of experiments were inadequate. Overall, the proposal lacked cohesion and did not present a comprehensive description of what would actually be performed. The PI is a young investigator who was very prolific as a postdoctoral fellow but has shown limited productivity as an independent researcher. The PI’s training is excellent, and the proposed research team and environment are good. In summary, this proposal addresses the role of a specific signaling pathway during reprogramming to hiPSCs. Despite its potential, the proposal lacked cohesion between individual ideas and their experimental execution, was based on inadequate preliminary data, and lacked compelling rationale.
- Ali Brivanlou